3GPP discusses a heterogeneous network. The heterogeneous network includes various types of cells (e.g. a macro cell, a femto cell, etc.) which coexist and operate therein. In the heterogeneous network, many nodes with low transmit power are located in an overlapping manner in the coverage of a macro cell. Examples of the nodes include a pico cell, a micro cell, a femto cell, a home eNB, etc. Since it is difficult for the conventional macro cell or micro cell division technology to meet increasing demands for data service, the heterogeneous network is constructed in such a manner that services are provided to small indoor and outdoor areas using a low-power pico cell, femto cell, relay node and the like to enable capacity increase at a low cost.
Although system capacity considerably increases in the heterogeneous network, there are many problems to be solved, such as a cell recognition problem due to shortage of cell IDs, the imbalance between an uplink coverage and a downlink coverage caused by different transmit powers of cells, and interference between a macro cell and a small cell or between small cells.
Among these problems, there has not yet been proposed solution to the interference between a macro cell and other heterogeneous cells, which affects a user equipment (UE) located at a cell boundary.